1. Field of the Invention
The invention relates to a semiconductor device and a manufacturing method thereof. More particularly, the invention relates to a non-volatile memory and a manufacturing method thereof.
2. Description of Related Art
Due to advantages such as the ability to repeatedly perform operations such as writing (or programming), reading, and erasing of data and retention of stored data even in a power failure, the non-volatile memory device has become a memory device widely adopted in personal computers and electronic equipment.
The traditional non-volatile memory device is generally designed to have a stacked-gate structure including a floating gate and a control gate manufactured through a doped polysilicon process. The floating gate is located between the control gate and the substrate, is in a floating state and not connected to any circuit, and the control gate is connected to a word line. Moreover, a tunneling oxide layer and an inter-gate dielectric layer respectively located between the substrate and the floating gate and between the floating gate and the control gate are further included.
Under the current trend of increased device density, the dimension of the device is reduced according to design specifications. In general, a greater gate coupling ratio between the floating gate and the control gate indicates a smaller working voltage needed for operation. However, as the density of the non-volatile memory is increased, an increase in gate coupling ratio may cause significant mutual interference between floating gates.
It can therefore be known that, in the current trend of miniaturized devices, how to balance device density and device reliability in limited space is a focus of study of various industries.